1. Field of the Invention
The present disclosure relates to a reflective display, and more particularly to a reflective touch display and a fabrication method thereof.
2. Description of the Related Art
Traditional reflective touch display 1, as illustrated in FIG. 1, comprises a touch screen 10, bonding layers 11 and 15, solid optical adhesive layers 12 and 14, a light guiding plate 13, and a reflective display device 16. The solid optical adhesive layers 12 and 14 are separately laminated on the top surface and lower surface of the light guiding plate 13. The bonding layers 11 and 15 are generally liquid optical adhesive layers. The light guiding plate 13 having the solid optical adhesive layers 12 and 14 is laminated to top surface of the reflective display device 16 through the bonding layer 15. The touch screen 10 is laminated on top surface of the solid optical adhesive layer 12 through the bonding layer 11.
While the external light source is sufficient, the reflective display device 16 reflects the external light source that is incident from the top surface of the touch screen 10 to display scripts and patterns on the screen 10 for users to view. However, if the external light source is insufficient, the reflective display device 16 can not reflect weak light source to display the scripts and patterns on the screen, and therefore a built-in light source 17 needs to be built in the reflective display device 16 for enough brightness. The built-in light source 17 can be set on side of the light guiding plate 13 to enable the built-in light source 17 incident into the light guiding plate 13. Refractive index of light guiding plate 13 can be greater than the refractive indexes of the solid optical adhesive layers 12 and 14. For example, if refractive index of the light guiding plate 13 is 1.52, then refractive indexes of the solid optical adhesive layers 12 and 14 are 1.47. According to optical principle, while the light transmits from optically denser medium to optically thinner medium, if the angle of incidence is greater than arcsin (1.47/1.52)≈75°, light can be fully reflected in optically denser medium, and therefore the light can be confined in the light guiding plate 13. By means of appropriately designing the light guiding plate 13, the built-in light source 17 can collect light dining the transmission in the light guiding plate 13 so that the reflective display device 16 is as bright as if it has a back light source and therefore the built-in light source 17 compensates for defect of shortage of back light source.
However, since the traditional reflective touch display 1 has to be laminated multiple times, the corresponding fabrication process is comparatively complicated, which reduced the optical property of products. Moreover, viscidity of the solid optical adhesive layer 12 and the bonding layer 11 is different. Hence, the solid optical adhesive layer 12 and the bonding layer 11 may separate from each other because of incompatibility of two different kinds of adhesives.